Fig 2: Changes in urine biomarker Levels of patients with SLE without LN and patients with LN only follow-up. (A) Urine level of ALCAM. (B) Urine level of HPX. (C) Urine level of PRDX6. Statistical analyses were conducted using the Mann–Whitney U test. SLE, systemic lupus erythematosus; LN, lupus nephritis; ALCAM, activated leukocyte cell adhesion molecule; HPX, hemopexin; PRDX, peroxiredoxin.

Fig 3: Changes in urine biomarker levels in follow-up observations of patients with SLE without LN and patients with LN. (A) Urine level of ALCAM. (B) Urine level of HPX. (C) Urine level of PRDX6. Statistical analyses were conducted using the Mann–Whitney U test. SLE, systemic lupus erythematosus; LN, lupus nephritis; ALCAM, activated leukocyte cell adhesion molecule; HPX, hemopexin; PRDX, peroxiredoxin.

Fig 4: Association between changes in biomarker levels and disease activity during follow-up examinations. (A) Correlation between ΔALCAM and ΔSLEDAI-2k. (B) Correlation between HPX and SLEDAI-2k. (C) Correlation between Δ PRDX6 and ΔSLEDAI-2k. SLEDAI, SLE disease activity index 2000; ALCAM, activated leukocyte cell adhesion molecule; HPX, hemopexin; PRDX, peroxiredoxin.

Fig 5: ROC curves for urine ALCAM, HPX, and PRDX in the diagnosis of SLE and LN compared to healthy controls. (A) For SLE (non-renal + renal) diagnosis, the AUC was 0.801 for the urine ALCAM (95% CI, 0.734 – 0.868), 0.707 for the urine hemopexin (95% CI, 0.622 – 0.792), and 0.697 for the urine PRDX (95% CI, 0.612 – 0.782). (B) For LN diagnosis, the AUC was 0.850 for the urine ALCAM (95% CI, 0.778 – 0.921), 0.781 for the urine hemopexin (95% CI, 0.695 – 0.867), and 0.714 for the urine PRDX (95% CI, 0.617 – 0.812). ROC, Receiver operating characteristic; SLE, systemic lupus erythematosus; LN, lupus nephritis; ALCAM, activated leukocyte cell adhesion molecule; HPX, hemopexin; PRDX, peroxiredoxin; AUC, area under the receiver operating characteristic curve; CI, confidence interval.